Touch-sensitive sensor surfaces, such as a touchpad on a laptop or a touch screen, that generate signals dependent on the placement and/or movement of a finger physically contacting the sensor surface, are known in the art. The movement of the finger may be defined in terms of direction, speed and/or acceleration. Known sensor surfaces that are adapted to record a finger's arbitrary two-dimensional placement and/or movement are substantially smooth.
Many computer programs have a broad margin for correctly controlling the cursor during vertical movements, whereas controlling the cursor during horizontal movements is more problematic. This is for example the case when choosing between submenus.
Recent studies have shown that the use of touchpads may lead to injuries substantially corresponding to so-called mouse injuries, the injury merely being to other muscles and tendons. The use of a touchpad requires even more fine motor skills than the use of a mouse. Being forced to use a touchpad when working on a laptop is thus usually a source of irritation. In addition, the use of common touchpads poses problems for people with disabilities.